The present invention relates to a new and improved method and apparatus in which a wedge member is used to change a spatial relationship between portions of a bone in a patient""s body.
A known method for performing an osteotomy includes forming a slot which extends part way through a bone. A forked wedge tool is inserted into the slot. A plate is then placed in a central opening in the forked wedge tool and positioned against the bone. The plate is secured to the bone. The forked wedge tool is then removed from the opening. This method of performing an osteotomy is disclosed in U.S. Pat. No. 5,620,448.
The foregoing osteotomy changes the spatial relationship between portions of a bone in a patient""s body by forming and maintaining a wedge-shaped opening in the bone. In other known methods, the spatial relationship between portions of a bone in a patient""s body has been changed by removing a wedged-shaped piece from the bone. The resulting opening is closed to effect the relative movement between portions of the bone. The performance of an osteotomy which includes removing a wedge-shaped piece of bone is disclosed in U.S. Pat. Nos. 5,053,039 and 5,601,565.
The present invention relates to a new and improved method and apparatus for use in changing a spatial relationship between portions of a bone in a patient""s body. When this is to be done, an opening is formed in a portion of the patient""s body tissue to at least partially expose the bone. Force is applied to the bone with a wedge member to move one portion of the bone relative to another portion of the bone. The wedge member may be fixedly connected with either or both portions of the bone. The opening in the patient""s body is then closed with the wedge member disposed in engagement with the bone. Force can be transmitted between portions of the bone through the wedge member.
The wedge member may taper from a thick edge to a thin edge and have a side surface which extends from one end of the thin edge, along the thick edge, to the opposite end of the thin edge. The side surface of the wedge member may have a cross sectional configuration corresponding to the configuration of a portion of an outer side surface of the bone. This enables the wedge member to be aligned with the outer side surface of the bone.
The wedge member may be positioned relative to the bone at a location where a layer of hard cortical bone encloses soft cancellous bone. Opposite ends of the thin leading edge of the wedge member may be positioned in engagement with the hard cortical bone while a central portion of the thin edge of the wedge member engages the soft cancellous bone. In addition, the layer of hard cortical bone may engage the wedge member adjacent to the side surface of the wedge member.
It is contemplated that the wedge member may have many different constructions. It is believed that it will be advantageous to form the wedge member with one or more openings through which bone can grow. The wedge member may be coated with and/or contain bone growth promoting material. The wedge member may be hollow and contain material which promotes growth of bone through the wedge member.
A screw member may extend ahead of the thin leading edge of the wedge member and engage hard cortical bone. Force may be transmitted from the screw member to the wedge member to move the wedge member relative to the bone. Alternatively, the wedge member may have a circular cross sectional configuration with an external thread convolution to enable the wedge member to be moved into an opening in a bone by rotating the wedge member.